Depending on the file size, the importer may take a few minutes to completely process the
spreadsheet, on completion you will receive a report either telling you all the products will be uploaded successfully or if there are any errors for you to fix.
[Bonus Tip] Even if a few errors are displayed, the rest of your file will still have been imported
successfully, so there is no need to re-upload everything, simply make a note and fix the errors
displayed and re-upload those products.